diff --git a/reactos/lib/rtl/heap_rewrite.c b/reactos/lib/rtl/heap_rewrite.c
index 7bc9dff9f6c..2c28b6a76d7 100644
--- a/reactos/lib/rtl/heap_rewrite.c
+++ b/reactos/lib/rtl/heap_rewrite.c
@@ -3216,7 +3216,7 @@ RtlSizeHeap(
     }
 
     /* Force flags */
-    Flags |= Heap->Flags;
+    Flags |= Heap->ForceFlags;
 
     /* Call special heap */
     if (RtlpHeapIsSpecial(Flags))